Crotalus simus
Silhouette: Bill Bouton (source photo) & T. Michael Keesey (vectorization) · PhyloPic
In 3 days ~50% in a week ~80%
Common names: Middle American rattlesnake, Central American rattlesnake, tzabcan (local name for subspecies C. s. tzabcan) Crotalus simus is a venomous pit viper species found in Mexico and Central America. The specific epithet is Latin for "flat-nosed", likely because its head is blunt compared with lanceheads (Bothrops).
Adults commonly exceed 130 cm (51 in) in length, with males growing larger than females. Large males reach 140–160 cm (55–63 in) in some populations. The maximum length is 180 cm (71 in). The body has a rough appearance because the dorsal scale keels are accentuated into protuberances or tuberculations. This is most apparent on the scale rows on either side of the body with a decreasing intensity in the lower rows. The vertebral scales are about as prominently keeled as the fourth row down on the flanks (with the vertebral scales as the first row).
The species is found from Mexico in southwestern Michoacán on the Pacific coast, and Veracruz and the Yucatan Peninsula on the Atlantic coast, south through Belize, Guatemala, El Salvador, Honduras, and Nicaragua to west-central Costa Rica. It is absent from Panama, but apparently... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Santa Rosa National Park | 🇨🇷 Costa Rica | |
| 2 | Celaque National Park | 🇭🇳 Honduras | |
| 3 | Ostional Wildlife Refuge | 🇨🇷 Costa Rica |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Zoológico de Brasília | 🇧🇷 Brazil | |
| 2 | Guadalajara Zoo | 🇲🇽 Mexico | |
| 3 | La Paz Waterfall Gardens | 🇨🇷 Costa Rica | |
| 4 | Safari Masai Mara | 🇲🇽 Mexico | |
| 5 | Zoológico Thomas Belt | 🇳🇮 Nicaragua | |
| 6 | Parque Zoológico Nacional Simón Bolívar | 🇨🇷 Costa Rica | |
| 7 | La Aurora Zoo | 🇬🇹 Guatemala | |
| 8 | Monteverde Theme Park | 🇨🇷 Costa Rica | |
| 9 | Zoológico Miguél Álvarez del Toro | 🇲🇽 Mexico |
No species of the same family or order lives in Ostional Wildlife Refuge, so these are its closest relatives here: other reptiles.
Possible
About 20% of wildlife watchers report a Central American Rattlesnake sighting in Ostional Wildlife Refuge on a given day, based on 9 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 16th most-seen of the 20 reptiles we can rate there. Over three days the chance rises to about 50%, and over a week to about 80%, if each day is a fresh chance.
July and November
In those months about 30% of wildlife watchers report a Central American Rattlesnake in Ostional Wildlife Refuge on a given day, against under 5% in August–October and December–May, the lowest months.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Central American Rattlesnake sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is seen both by day and at night.
3rd of 3
Of the 3 parks where we can rate Central American Rattlesnake sightings, Ostional Wildlife Refuge ranks 3rd at about 20%. The best odds are in Santa Rosa National Park (Costa Rica, about 40%) and Celaque National Park (Honduras, about 30%).
GBIF citizen-science records
It is estimated from how often the Central American Rattlesnake is recorded against all the reptiles logged in Ostional Wildlife Refuge (9 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
